#22808 Move CoupledTerminationFlow to Flow.fromSinkAndSourceCoupled

Also mention coupled variant in the uncoupled scaladoc

akka-docs/src/main/paradox/java/stream/stages-overview.md

@@ -1059,16 +1059,14 @@ Creates a `Flow` from a `Sink` and a `Source` where the Flow's input will be sen
 and the `Flow` 's output will come from the Source.
 
 Note that termination events, like completion and cancelation is not automatically propagated through to the "other-side"
-of the such-composed Flow. Use `CoupledTerminationFlow` if you want to couple termination of both of the ends,
+of the such-composed Flow. Use `Flow.fromSinkAndSourceCoupled` if you want to couple termination of both of the ends,
 for example most useful in handling websocket connections.
 
 ---------------------------------------------------------------
 
-### CoupledTerminationFlow.fromSinkAndSource
+### Flow.fromSinkAndSourceCoupled
 
 Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow them them.
-Similar to `Flow.fromSinkAndSource` however that API does not connect the completion signals of the wrapped stages.
-
 Similar to `Flow.fromSinkAndSource` however couples the termination of these two stages.
 
 E.g. if the emitted `Flow` gets a cancellation, the `Source` of course is cancelled,

akka-docs/src/main/paradox/scala/stream/stages-overview.md

@@ -1047,16 +1047,14 @@ Creates a `Flow` from a `Sink` and a `Source` where the Flow's input will be sen
 and the `Flow` 's output will come from the Source.
 
 Note that termination events, like completion and cancelation is not automatically propagated through to the "other-side"
-of the such-composed Flow. Use `CoupledTerminationFlow` if you want to couple termination of both of the ends,
+of the such-composed Flow. Use `Flow.fromSinkAndSourceCoupled` if you want to couple termination of both of the ends,
 for example most useful in handling websocket connections.
 
 ---------------------------------------------------------------
 
-### CoupledTerminationFlow.fromSinkAndSource
+### Flow.fromSinkAndSourceCoupled
 
 Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow them them.
-Similar to `Flow.fromSinkAndSource` however that API does not connect the completion signals of the wrapped stages.
-
 Similar to `Flow.fromSinkAndSource` however couples the termination of these two stages.
 
 E.g. if the emitted `Flow` gets a cancellation, the `Source` of course is cancelled,

akka-stream-tests/src/test/scala/akka/stream/scaladsl/CoupledTerminationFlowSpec.scala

@@ -6,10 +6,12 @@ package akka.stream.scaladsl
 import akka.{ Done, NotUsed }
 import akka.stream._
 import akka.stream.testkit._
+import akka.stream.testkit.scaladsl.{ TestSink, TestSource }
 import akka.testkit.TestProbe
 import org.reactivestreams.{ Publisher, Subscriber, Subscription }
 import org.scalatest.Assertion
 
+import scala.concurrent.Future
 import scala.util.{ Failure, Success, Try }
 import scala.xml.Node
 
@@ -72,7 +74,7 @@ class CoupledTerminationFlowSpec extends StreamSpec with ScriptedTest {
         val (innerSink, innerSinkAssertion) = interpretInnerSink(innerSinkRule)
         val (innerSource, innerSourceAssertion) = interpretInnerSource(innerSourceRule)
 
-        val flow = CoupledTerminationFlow.fromSinkAndSource(innerSink, innerSource)
+        val flow = Flow.fromSinkAndSourceCoupledMat(innerSink, innerSource)(Keep.none)
         outerSource.via(flow).to(outerSink).run()
 
         outerAssertions()
@@ -83,9 +85,9 @@ class CoupledTerminationFlowSpec extends StreamSpec with ScriptedTest {
 
     "completed out:Source => complete in:Sink" in {
       val probe = TestProbe()
-      val f = CoupledTerminationFlow.fromSinkAndSource(
+      val f = Flow.fromSinkAndSourceCoupledMat(
         Sink.onComplete(d ⇒ probe.ref ! "done"),
-        Source.empty) // completes right away, should complete the sink as well
+        Source.empty)(Keep.none) // completes right away, should complete the sink as well
 
       f.runWith(Source.maybe, Sink.ignore) // these do nothing.
 
@@ -94,7 +96,7 @@ class CoupledTerminationFlowSpec extends StreamSpec with ScriptedTest {
 
     "cancel in:Sink => cancel out:Source" in {
       val probe = TestProbe()
-      val f = CoupledTerminationFlow.fromSinkAndSource(
+      val f = Flow.fromSinkAndSourceCoupledMat(
         Sink.cancelled,
         Source.fromPublisher(new Publisher[String] {
           override def subscribe(subscriber: Subscriber[_ >: String]): Unit = {
@@ -104,7 +106,7 @@ class CoupledTerminationFlowSpec extends StreamSpec with ScriptedTest {
               override def request(l: Long): Unit = () // do nothing
             })
           }
-        })) // completes right away, should complete the sink as well
+        }))(Keep.none) // completes right away, should complete the sink as well
 
       f.runWith(Source.maybe, Sink.ignore) // these do nothing.
 
@@ -113,15 +115,27 @@ class CoupledTerminationFlowSpec extends StreamSpec with ScriptedTest {
 
     "error wrapped Sink when wrapped Source errors " in {
       val probe = TestProbe()
-      val f = CoupledTerminationFlow.fromSinkAndSource(
+      val f = Flow.fromSinkAndSourceCoupledMat(
         Sink.onComplete(e ⇒ probe.ref ! e.failed.get.getMessage),
-        Source.failed(new Exception("BOOM!"))) // completes right away, should complete the sink as well
+        Source.failed(new Exception("BOOM!")))(Keep.none) // completes right away, should complete the sink as well
 
       f.runWith(Source.maybe, Sink.ignore) // these do nothing.
 
       probe.expectMsg("BOOM!")
     }
 
+    "support usage with Graphs" in {
+      val source: Graph[SourceShape[Int], TestPublisher.Probe[Int]] = TestSource.probe[Int]
+      val sink: Graph[SinkShape[Any], Future[Done]] = Sink.ignore
+
+      val flow = Flow.fromSinkAndSourceCoupledMat(sink, source)(Keep.right)
+
+      val (source1, source2) = TestSource.probe[Int].viaMat(flow)(Keep.both).toMat(Sink.ignore)(Keep.left).run
+
+      source1.sendComplete()
+      source2.expectCancellation()
+    }
+
   }
 
   def interpretOuter(rule: String): (Source[String, NotUsed], Sink[String, NotUsed], () ⇒ Any) = {

akka-stream/src/main/scala/akka/stream/javadsl/CoupledTerminationFlow.scala

@@ -56,6 +56,7 @@ object CoupledTerminationFlow {
    *
    * The order in which the `in` and `out` sides receive their respective completion signals is not defined, do not rely on its ordering.
    */
+  @deprecated("Use `Flow.fromSinkAndSourceCoupledMat(..., ..., Keep.both())` instead", "2.5.2")
   def fromSinkAndSource[I, O, M1, M2](in: Sink[I, M1], out: Source[O, M2]): Flow[I, O, (M1, M2)] =
-    akka.stream.scaladsl.CoupledTerminationFlow.fromSinkAndSource(in.asScala, out.asScala).asJava
+    akka.stream.scaladsl.Flow.fromSinkAndSourceCoupledMat(in, out)(akka.stream.scaladsl.Keep.both).asJava
 }

akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala

@@ -55,18 +55,98 @@ object Flow {
     }
 
   /**
-   * Helper to create `Flow` from a `Sink`and a `Source`.
+   * Creates a `Flow` from a `Sink` and a `Source` where the Flow's input
+   * will be sent to the Sink and the Flow's output will come from the Source.
+   *
+   * The completion of the Sink and Source sides of a Flow constructed using
+   * this method are independent. So if the Sink receives a completion signal,
+   * the Source side will remain unaware of that. If you are looking to couple
+   * the termination signals of the two sides use `Flow.fromSinkAndSourceCoupled` instead.
    */
   def fromSinkAndSource[I, O](sink: Graph[SinkShape[I], _], source: Graph[SourceShape[O], _]): Flow[I, O, NotUsed] =
     new Flow(scaladsl.Flow.fromSinkAndSourceMat(sink, source)(scaladsl.Keep.none))
 
   /**
-   * Helper to create `Flow` from a `Sink`and a `Source`.
+   * Creates a `Flow` from a `Sink` and a `Source` where the Flow's input
+   * will be sent to the Sink and the Flow's output will come from the Source.
+   *
+   * The completion of the Sink and Source sides of a Flow constructed using
+   * this method are independent. So if the Sink receives a completion signal,
+   * the Source side will remain unaware of that. If you are looking to couple
+   * the termination signals of the two sides use `Flow.fromSinkAndSourceCoupledMat` instead.
+   *
+   * The `combine` function is used to compose the materialized values of the `sink` and `source`
+   * into the materialized value of the resulting [[Flow]].
    */
   def fromSinkAndSourceMat[I, O, M1, M2, M](
     sink: Graph[SinkShape[I], M1], source: Graph[SourceShape[O], M2],
     combine: function.Function2[M1, M2, M]): Flow[I, O, M] =
     new Flow(scaladsl.Flow.fromSinkAndSourceMat(sink, source)(combinerToScala(combine)))
+
+  /**
+   * Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them.
+   * Similar to [[Flow.fromSinkAndSource]] however couples the termination of these two stages.
+   *
+   * E.g. if the emitted [[Flow]] gets a cancellation, the [[Source]] of course is cancelled,
+   * however the Sink will also be completed. The table below illustrates the effects in detail:
+   *
+   * <table>
+   *   <tr>
+   *     <th>Returned Flow</th>
+   *     <th>Sink (<code>in</code>)</th>
+   *     <th>Source (<code>out</code>)</th>
+   *   </tr>
+   *   <tr>
+   *     <td><i>cause:</i> upstream (sink-side) receives completion</td>
+   *     <td><i>effect:</i> receives completion</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>cause:</i> upstream (sink-side) receives error</td>
+   *     <td><i>effect:</i> receives error</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>cause:</i> downstream (source-side) receives cancel</td>
+   *     <td><i>effect:</i> completes</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>effect:</i> cancels upstream, completes downstream</td>
+   *     <td><i>effect:</i> completes</td>
+   *     <td><i>cause:</i> signals complete</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>effect:</i> cancels upstream, errors downstream</td>
+   *     <td><i>effect:</i> receives error</td>
+   *     <td><i>cause:</i> signals error or throws</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>effect:</i> cancels upstream, completes downstream</td>
+   *     <td><i>cause:</i> cancels</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   * </table>
+   *
+   */
+  def fromSinkAndSourceCoupled[I, O](sink: Graph[SinkShape[I], _], source: Graph[SourceShape[O], _]): Flow[I, O, NotUsed] =
+    new Flow(scaladsl.Flow.fromSinkAndSourceCoupled(sink, source))
+
+  /**
+   * Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them.
+   * Similar to [[Flow.fromSinkAndSource]] however couples the termination of these two stages.
+   *
+   * E.g. if the emitted [[Flow]] gets a cancellation, the [[Source]] of course is cancelled,
+   * however the Sink will also be completed. The table on [[Flow.fromSinkAndSourceCoupled]]
+   * illustrates the effects in detail.
+   *
+   * The `combine` function is used to compose the materialized values of the `sink` and `source`
+   * into the materialized value of the resulting [[Flow]].
+   */
+  def fromSinkAndSourceCoupledMat[I, O, M1, M2, M](
+    sink: Graph[SinkShape[I], M1], source: Graph[SourceShape[O], M2],
+    combine: function.Function2[M1, M2, M]): Flow[I, O, M] =
+    new Flow(scaladsl.Flow.fromSinkAndSourceCoupledMat(sink, source)(combinerToScala(combine)))
 }
 
 /** Create a `Flow` which can process elements of type `T`. */

akka-stream/src/main/scala/akka/stream/scaladsl/CoupledTerminationFlow.scala

@@ -59,15 +59,9 @@ object CoupledTerminationFlow {
    *
    * The order in which the `in` and `out` sides receive their respective completion signals is not defined, do not rely on its ordering.
    */
+  @deprecated("Use `Flow.fromSinkAndSourceCoupledMat(..., ...)(Keep.both)` instead", "2.5.2")
   def fromSinkAndSource[I, O, M1, M2](in: Sink[I, M1], out: Source[O, M2]): Flow[I, O, (M1, M2)] =
-      // format: OFF
+    Flow.fromSinkAndSourceCoupledMat(in, out)(Keep.both)
-      Flow.fromGraph(GraphDSL.create(in, out)(Keep.both) { implicit b => (i, o) =>
-        import GraphDSL.Implicits._
-        val bidi = b.add(new CoupledTerminationBidi[I, O])
-        /* bidi.in1 ~> */ bidi.out1 ~> i; o ~> bidi.in2 /* ~> bidi.out2 */
-        FlowShape(bidi.in1, bidi.out2)
-      })
-  // format: ON
 
 }
 

akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala

@@ -315,6 +315,11 @@ object Flow {
   /**
    * Creates a `Flow` from a `Sink` and a `Source` where the Flow's input
    * will be sent to the Sink and the Flow's output will come from the Source.
+   *
+   * The completion of the Sink and Source sides of a Flow constructed using
+   * this method are independent. So if the Sink receives a completion signal,
+   * the Source side will remain unaware of that. If you are looking to couple
+   * the termination signals of the two sides use `Flow.fromSinkAndSourceCoupled` instead.
    */
   def fromSinkAndSource[I, O](sink: Graph[SinkShape[I], _], source: Graph[SourceShape[O], _]): Flow[I, O, NotUsed] =
     fromSinkAndSourceMat(sink, source)(Keep.none)
@@ -323,11 +328,86 @@ object Flow {
    * Creates a `Flow` from a `Sink` and a `Source` where the Flow's input
    * will be sent to the Sink and the Flow's output will come from the Source.
    *
+   * The completion of the Sink and Source sides of a Flow constructed using
+   * this method are independent. So if the Sink receives a completion signal,
+   * the Source side will remain unaware of that. If you are looking to couple
+   * the termination signals of the two sides use `Flow.fromSinkAndSourceCoupledMat` instead.
+   *
    * The `combine` function is used to compose the materialized values of the `sink` and `source`
    * into the materialized value of the resulting [[Flow]].
    */
   def fromSinkAndSourceMat[I, O, M1, M2, M](sink: Graph[SinkShape[I], M1], source: Graph[SourceShape[O], M2])(combine: (M1, M2) ⇒ M): Flow[I, O, M] =
     fromGraph(GraphDSL.create(sink, source)(combine) { implicit b ⇒ (in, out) ⇒ FlowShape(in.in, out.out) })
+
+  /**
+   * Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them.
+   * Similar to [[Flow.fromSinkAndSource]] however couples the termination of these two stages.
+   *
+   * E.g. if the emitted [[Flow]] gets a cancellation, the [[Source]] of course is cancelled,
+   * however the Sink will also be completed. The table below illustrates the effects in detail:
+   *
+   * <table>
+   *   <tr>
+   *     <th>Returned Flow</th>
+   *     <th>Sink (<code>in</code>)</th>
+   *     <th>Source (<code>out</code>)</th>
+   *   </tr>
+   *   <tr>
+   *     <td><i>cause:</i> upstream (sink-side) receives completion</td>
+   *     <td><i>effect:</i> receives completion</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>cause:</i> upstream (sink-side) receives error</td>
+   *     <td><i>effect:</i> receives error</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>cause:</i> downstream (source-side) receives cancel</td>
+   *     <td><i>effect:</i> completes</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>effect:</i> cancels upstream, completes downstream</td>
+   *     <td><i>effect:</i> completes</td>
+   *     <td><i>cause:</i> signals complete</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>effect:</i> cancels upstream, errors downstream</td>
+   *     <td><i>effect:</i> receives error</td>
+   *     <td><i>cause:</i> signals error or throws</td>
+   *   </tr>
+   *   <tr>
+   *     <td><i>effect:</i> cancels upstream, completes downstream</td>
+   *     <td><i>cause:</i> cancels</td>
+   *     <td><i>effect:</i> receives cancel</td>
+   *   </tr>
+   * </table>
+   *
+   */
+  def fromSinkAndSourceCoupled[I, O](sink: Graph[SinkShape[I], _], source: Graph[SourceShape[O], _]): Flow[I, O, NotUsed] =
+    fromSinkAndSourceCoupledMat(sink, source)(Keep.none)
+
+  /**
+   * Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow from them.
+   * Similar to [[Flow.fromSinkAndSource]] however couples the termination of these two stages.
+   *
+   * E.g. if the emitted [[Flow]] gets a cancellation, the [[Source]] of course is cancelled,
+   * however the Sink will also be completed. The table on [[Flow.fromSinkAndSourceCoupled]]
+   * illustrates the effects in detail.
+   *
+   * The `combine` function is used to compose the materialized values of the `sink` and `source`
+   * into the materialized value of the resulting [[Flow]].
+   */
+  def fromSinkAndSourceCoupledMat[I, O, M1, M2, M](sink: Graph[SinkShape[I], M1], source: Graph[SourceShape[O], M2])(combine: (M1, M2) ⇒ M): Flow[I, O, M] =
+  // format: OFF
+    Flow.fromGraph(GraphDSL.create(sink, source)(combine) { implicit b => (i, o) =>
+      import GraphDSL.Implicits._
+      val bidi = b.add(new CoupledTerminationBidi[I, O])
+      /* bidi.in1 ~> */ bidi.out1 ~> i; o ~> bidi.in2 /* ~> bidi.out2 */
+      FlowShape(bidi.in1, bidi.out2)
+    })
+  // format: ON
 }
 
 object RunnableGraph {